title: Four new two-photon polymerization initiators with varying donor and conjugated bridge: synthesis and two-photon activity.
abstract: A specific series of dumbbell-shaped bis-carbazoles or bis-phenothiazines dyes (1, 2, 3 and 4) constructed with styrene or biphenylethyne as the π-bridge have been synthesized and characterized. Detailed spectral properties including linear absorption, one and two-photon fluorescence properties were investigated. The results show that extending conjugated chain and introducing donors have substantial effect on their photophysical properties. Among them, two-photon absorption cross sections (σ) of the four dyes in DMF determined by the Z-scan technique are successively increased from 1 to 4 with enhancing electron-donating ability and extending conjugated chain, but electron-donating ability has larger contribution to the σ values than extending conjugated chain based on the comparison of small molecules (D-π-D). Two-photon initiation polymerization (TPIP) microfabrication experiments have been carried out using compound 4 as an initiator under irradiation of 200 fs, 76 MHz femtosecond laser at 760 nm. The results confirm that the four dyes can be effectively used as organic two-photon photopolymerization initiators.
authors.affiliation: Department of Chemistry, Fuyang Normal College, Fuyang 236036, China; Department of Chemistry and Chemical Engineering, Anhui University, Hefei 230039, China.
authors.forename: Fuying
authors.initials: F
authors.lastname: Hao
authors.forename: Zhaodi
authors.initials: Z
authors.lastname: Liu
authors.forename: Mingliang
authors.initials: M
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Shengyi
authors.initials: S
authors.lastname: Zhang
authors.forename: Jieying
authors.initials: J
authors.lastname: Wu
authors.forename: Hongping
authors.initials: H
authors.lastname: Zhou
authors.forename: Yupeng
authors.initials: Y
authors.lastname: Tian
mesh_terms: D000114:Acetylene / Q000031:analogs & derivatives / Q000138:chemical synthesis; D002227:Carbazoles / Q000138:chemical synthesis*; D005456:Fluorescent Dyes / Q000138:chemical synthesis*; D010640:Phenothiazines / Q000138:chemical synthesis*; D017785:Photons; D058105:Polymerization; D013050:Spectrometry, Fluorescence; D020058:Styrene / Q000138:chemical synthesis
chemical_list: D002227:Carbazoles; D005456:Fluorescent Dyes; D010640:Phenothiazines; C044736:phenylacetylene; D020058:Styrene; D000114:Acetylene
keywords: Dyes; Photopolymerization initiator; Two-photon absorption; Z-scan technique